Integrated circuits having analog and digital circuitry often include digital interface circuits and level-shift circuits. The digital interface circuits provide inputs to and receive outputs from the digital circuitry, allowing the analog circuitry to communicate with the digital circuitry. Digital interface circuits can often support multiple modes of operation. For example, some digital interface circuits include pins that can form a serial-type interface or a parallel-type interface depending on their mode of operation.
The digital interface circuits often operate at logic levels that differ from analog supply voltages. In those cases, the level-shift circuits perform logic-level translations, shifting voltages from the analog supply voltages to digital logic levels and vice versa. Often times, at least one input pin can be used to provide one or more input voltages, where the input voltages define the digital logic levels used by level-shift circuits.